


just wing it

by yensidlove



Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, M/M, Sibling Incest, Underswap Papyrus, Underswap Sans, but otherwise it's just fluff so, masturbation is like mentioned and there's some mentions of other stuff vaguely
Language: English
Status: Completed
Published: 2016-02-24
Updated: 2016-02-24
Packaged: 2018-05-22 23:59:15
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,611
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6098209
Author URL: https://archiveofourown.org/users/yensidlove/pseuds/yensidlove
Summary: <blockquote class="userstuff">
              <p>Sans isn't as uninformed as Papyrus thinks he is. It's about time he set his brother straight.</p>
            </blockquote>





	just wing it

**Author's Note:**

> so this is the first fic i'm publishing on here... and it's fontcest. i feel like i shouldn't be surprised. hope you guys enjoy it, lemme know if you see anything that needs fixing.

Breakfast, morning, croissants and coffee. Sans accompanied Papyrus to Muffet's as part of his early bird patrol route. It was a daily occurrence, excluding the days where Papyrus was dead as a door-nail asleep on the couch after days of not getting any shut-eye at all. Sans had started it as tradition to make sure his perpetually tired brother didn't keel over on the way to refuel. He stuck around to joke with Muffet and chat with a few monsters about the last attempt he'd made at burritos— a disaster— but slowly wound up on his way out.

The crowd had picked up since he came in. As he made to leave Muffet handed him a bottle of honey and asked him for assistance by way of a three-armed motion. She didn't need to, he understood perfectly. Sans turned with a cheery salute to the spider monster and brought the honey over to where Papyrus was seated.

Upon his approach, however, he overheard the tail-end of what must have been a rather lewd conversation if Papyrus's orange cheekbones were any indicator. The other monsters at the table giggled. He turned away after he handed Papyrus the honey, unbothered by the probably-phallic tomfoolery. Then he heard his brother speak.

"whoa there guys, shh, not in front of sans, alright?"

_not in front of sans..._

The air went suddenly cold in the warm cafe. Sans furrowed his bony brow, half way to the door. An insistent remark in his defense was enough to chill the room around the short skeleton. The outside, in the freezing cold of Snowdin, would have been more welcome.

He peeked over his shoulder pad at the taller skeleton. Papyrus hushed the monsters and shot a careful look in Sans' direction just as his brother looked away.

Sans bid Muffet goodbye and left with a wave to Papyrus, who waved back. In his wake, Papyrus was none the wiser. On the walk back home, Sans was distracted. Too deep in thought to even check the mail

 

* * *

 

By the time Papyrus got home for lunch and Sans returned from his noon patrol, the shorter of the two had made up his mind.

He had a bone to pick with his bro.

"I know what a dick is, Papy." From in the living room, Papyrus choked on the taco he had been about to swallow. He coughed once, twice and then cleared his throat with a strained noise.

"sans, ah.. nyeheh.. you wanna run that by me again?"

"I know what a dick is," Sans repeated, tone entirely serious as he washed dishes in the kitchen. The pans clanked loudly with the force of his motions, but with Sans' volume Papyrus heard every word clear as day. He wished he didn't. "I'm not some babybones! I'm older than you. I know what sex is—"

"oh. wow. so, uh.. yeah. on the list of _Things I Didn't Wanna Talk About Today_ that, uh, that one takes the cake."

Sans pointedly shut off the water and huffed. Papyrus sunk lower on the couch. "I'm just saying you don't have to try to cover my ears or.. beat around the bush." He trotted to the kitchen door and gave his brother a Look. "I'm an adult monster! I know how these things work..

For example! I've known what those stains on your sheets are since they started appearing. I mean, we're only a few walls apart, it's not like it's soundproof—"

"uhhh," Papyrus looked more flustered by the second. Eyebrows high, the lazy monster teetered on the edge of panic. His brother implied... he'd _heard him._ That could only mean one thing. He'd heard him when he..? When he called out his—?

Papyrus sat back more, hunched in farther. Everything in his mind screamed in horrified unison. Meanwhile, Sans hadn't even slowed down.

"—So you don't have to pretend like you drink milk- which I know you don't do! Even though you really _should_ , Papy, we're skeletons right we could use the calcium!"

Papyrus let out a weak chuckle and sweat formed on his skeletal brow, "brother i swear, i'll go drink an _entire gallon_ right this minute if we can stop having this conversation—"

Sans held up a slightly soapy hand and talked over Papyrus, "I know exactly why Alphys cancels our training sessions sometimes to go spend some _~quality time~_ with Undyne," Papyrus curled in more, if it was possible. Voices weren't allowed to sound that suggestive, especially not from a cute little monster like his brother Sans.

"And Alphys isn't shy about it, it's no big deal! I also know that some of the monsters in Waterfall have a monthly circle jerk! And circle jerks are nothing to be ashamed of, y'know." Sans paused and undid his apron, expression matter-of-fact. Papyrus winced.

"hey uh can we agree to not ever use the term 'circle jerk' again?" He joked halfheartedly.

"Papy!"

"i'm just saying, it's kind of a gross phrase tibia honest."

"Papy!! I'm being serious here!" Sans pouted and stomped one foot, which was more comical than intimidating. It made Papyrus relax fractionally.

He sighed and momentarily extracted a hand from his hoodie to scratch sheepishly at his skull. Of course he knew Sans was older, and more experienced, but something about the skeleton's bright disposition made Papyrus concerned for his innocence. "sans..."

Sans was his heart and soul. The taller skeleton only wanted to take care of him, look out for him. Same as Sans did for Papyrus.

To his credit, Sans smiled sadly. "I appreciate that you try to protect me, I do. You're the best bro a monster could ask for!" Papyrus chuckled at the compliment and Sans seemed to fidget over his next words. "I just.. I just want you to know that I know enough to keep myself safe, okay? You already never get sleep, you don't need the extra stress."

Papyrus shook his head at the notion that he could possibly not worry over his brother, but shrugged in agreement to the sentiment. Sans seemed appeased. He smiled and turned to go back into the kitchen. But just as he did Papyrus blurted, "if you.. ah, nevermind."

"What! Papyrus. C'mon." Sans grinned at him and came back into the living room, eyes full of stars. His mood was restored.

Papyrus, awkward and halting, was less so in his element as he continued, "it's just. if you heard me, before..." He stopped again and eyed Sans critically, as if unsure how much he should give away. "What have you heard?"

It was Sans turn to look sheepish. He cleared his throat and blushed as he spoke, eyes averted, "Well! I, uh. I try to give you your privacy, Pap! But.. unless I'm napping I do catch it. Most of it. I really don't want you to feel embarrassed or ashamed..." he trailed off, uncertain. Papyrus looked at his brother, searchingly. He waited patiently while the blue-faced skeleton fought a blush to work up the confidence to speak. Did Sans..?

"I don't mind that you call out my name! I don't. Honestly, it's very flattering!! You're an amazing, handsome skeleton, Papy. Any monster would be lucky to have you!" He paused, rubbed his bony fingers together shyly. "I mean, I feel lucky all the time! Mweheh," Sans grinned, confidence back in full force.

Papyrus looked at the floor while a fist clenched and relaxed inside his pocket. He took a long moment to digest the concept, then looked up and raised an eyebrow at Sans. "why didn't you ever say anything?"

"I figured, since we're bros and you know you can trust me with anything, you'd come forward and tell me when you were ready! I'm a skeleton with tact!" Sans adjusted the bandanna around his neck proudly. Papyrus snorted and stood up from the couch to follow Sans back into the kitchen. They both stood at the counter, quiet. Sans dried the clean dishes and handed them to Papyrus to put away. There was a time of comfortable silence as the pots were all replaced and the spatulas were put in their proper drawer.

Papyrus leaned against the door frame once it was all done and eyed his brother with mixed confusion and relief. "so. you're not even.. upset? or, or _freaked out_? that's it, just... you don't mind?"

"Nope!" Sans winked cheerily.

"at all?"

"Not at all, Papy!"

Papyrus blinked. "...huh."

As he seemed to come to terms with that information, Sans giggled and walked over to his bro. He made a gesture for Papyrus to bend down some, as if to tell a secret, and then propped up the last inch or two to clank his teeth against Papyrus' jaw affectionately. A sort-of-kiss.

"I love you, Papy." Sans poked Papyrus in the hip as if to make his point clear. Papyrus smiled, slow and easy.

"yeah.. yeah i love you, too, sans."

"Mweheheh.. good. Now! I've got to be at Alphys' place lickity split, so— mm!"

The taller skeleton muffled his counterparts words when he pressed his teeth snugly against the other's teeth. Sans face lit up once again with a blush, hearts in his eyes. Papyrus chuckled and scooped Sans into a hug and then off the ground into his arms. "you said alphys takes personal days off from training because of undyne... think maybe you could take one of those and spend some _~quality time~_ with me? we could have a date..."

Sans gasped and pressed his hands to his mouth. "A date!? Wowzers! But-! Well-! I'll have to get my dating manual—"

"it's alright, bro. i think we can wing it."


End file.
